During orthopic liver transplantation (OLT) a large transfusion of different blood components is frequently necessary. From 1981 to 1985 at the University Health Center in Pittsburgh, 4,318 units of RBCs and 4,788 units of platelets were administered during 366 OLT performed in adults. This results in a mean of 25 units of RBCs and 30 units of platelets per operation. The majority of adult liver transplant patients receive multiple transfusions of whole blood and/or blood components during their pretransplant course because of complications relating to their original disease. The exposure of these patients to different antigens from random donors facilitates the development of alloimmunization. The heightened alloimmune state can be identified by preoperative values of panel reacting antibodies (PRA). Since platelets possess the HLA antigens of donor specificity, platelets may function as the target of host antibodies, resulting in platelet alteration and subsequent dysfunction. Thus, the effect of alloimmunization on platelet function may be one of the factors responsible for significant blood loss after large transfusions of different blood components. In this retrospective study we compared blood loss and platelet transfusion during OLT with preoperative alloimmunization against random donor antigens, indicated by PRA values
